Settings Class with Metabox

gistfile1.php

<?php
/* Prevent loading this file directly and/or if the class is already defined */
if ( ! defined( 'ABSPATH' ) || class_exists( 'MYFX_Settings_Class' ) )
	return;


/**
 * Settings with Meta Boxes 
 * Helper class to easily create settings page for plugin or theme with Meta Box API.
 *
 * This settings page helper class is inspired by Hybrid Core Settings page by Justin Tadlock
 * and settings page with meta box example by Frank Bültge.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * @version 0.1.0
 * @author David Chandra Purnama <[email protected]>
 * @link http://shellcreeper.com
 * @link https://gist.github.com/turtlepod/5203512
 * @link https://github.com/justintadlock/hybrid-core
 * @link https://gist.github.com/bueltge/757903
 * @license http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * @copyright Copyright (c) 2013, David Chandra Purnama
 */
class MYFX_Settings_Class{

	/**
	 * @var $config the config for the settings
	 * @access public
	 */
	var $config;

	/**
	 * Class Constructor
	 * @param array $config the configuration required for the updater to work
	 * @return void
	 */
	public function __construct( $config = array() ) {

		/* default config */
		$defaults = array(

			/* register settings */
			'option_group'  => '',
			'option_name'   => '',

			/* add menu */
			'page_title'    => 'My Settings',
			'menu_title'    => 'My Settings Menu',
			'capability'    => 'manage_options',
			'slug'          => 'mysettings',

			/* add sub menu */
			'menu'          => 'Settings',
			'parent_slug'   => 'themes.php',

			/* add top level menu */
			'menu_icon'     => '',
			'position'      => 100,

			/* submit button */
			'submit'        => 'Update Settings',

			/* callback */
			'sanitize_callback' => '',
			'defaults_callback' => '',
		);

		/* merge configs and defaults */
		$this->config = wp_parse_args( $config, $defaults );
		$config = $this->config;
		
		/* load only when minimum req pass */
		if ( !empty( $config['option_group'] ) && !empty( $config['option_name'] ) ){

			add_action( 'admin_menu', array( &$this, 'setup' ) );

			if ( !empty( $config['sanitize_callback'] ) )
				add_filter( 'sanitize_option_' . $config['option_name'], $config['sanitize_callback'] );

			if ( !empty( $config['defaults_callback'] ) )
				add_filter( $config['slug'] . '_default_settings', $config['defaults_callback'] );
		}
	}

	/**
	 * Format settings data tor easy usage and sanitize
	 * @return array
	 */
	public function settings(){

		/* get config */
		$config = $this->config;

		/* settings array */
		$settings = array();
	
		/* id */
		$settings['id'] = esc_attr( $config['slug'] );

		/* register_settings_args */
		$settings['register'] = array(
			'option_group' => esc_attr( $config['option_group'] ),
			'option_name'  => esc_attr( $config['option_name'] ),
		);

		/* page context, submenu/parent menu */
		if ( $config['menu'] == 'toplevel' )
			$settings['context'] = esc_attr( 'menu' );
		else
			$settings['context'] = esc_attr( 'submenu' );

		/* add_page_args */
		$settings['page'] = array(
			'parent_slug'   => esc_attr( $config['parent_slug'] ),
			'page_title'    => esc_attr( $config['page_title'] ),
			'menu_title'    => esc_attr( $config['menu_title'] ),
			'capability'    => esc_attr( $config['capability'] ),
			'slug'          => sanitize_title( $config['slug'] ),
			'menu_icon'     => ( $config['menu_icon'] == 'div' ? 'div' : esc_url( $config['menu_icon'] ) );,
			'position'      => absint( $config['position'] ),
		);

		/* submit text */
		$settings['submit'] = esc_attr( $config['submit'] );

		return $settings;
	}

	/**
	 * Settings Page Hook
 	 * @return string
	 */
	public function page_hook() {
		$config = $this->config;
		$page_name = sanitize_title( $config['menu'] ) . '_page_' . $config['slug'];
		return $page_name;
	}

	/**
	 * Capability
	 * @return string
	 */
	public function capability() {
		$config = $this->config;
		return $config['capability'];
	}

	/**
	 * Settings Setup
	 * @return void
	 */
	public function setup() {

		/* get settings data */
		$settings = $this->settings();
		$add_page = $settings['page'];
		$page_hook = $this->page_hook();

		/* Register theme settings. */
		register_setting(
			$settings['register']['option_group'],
			$settings['register']['option_name']
		);

		/* Create the settings page. */
		if ( $settings['context'] == 'menu' ){
			$settings_page = add_menu_page(
				$add_page['page_title'],
				$add_page['menu_title'],
				$add_page['capability'],
				$add_page['slug'],
				array( &$this, 'settings_page' ),
				$add_page['menu_icon'],
				$add_page['position']
			);
		}
		else{
			$settings_page = add_submenu_page(
				$add_page['parent_slug'],
				$add_page['page_title'],
				$add_page['menu_title'],
				$add_page['capability'],
				$add_page['slug'],
				array( &$this, 'settings_page' )
			);
		}

		/* Check if the settings page is being shown before running any functions for it. */
		if ( !empty( $settings_page ) ) {

			/* Filter the settings page capability so that it recognizes the cap. */
			add_filter( "option_page_capability_{$page_hook}", array( &$this, 'capability' ) );

			/* Screen layout column */
			add_filter( 'screen_layout_columns', array( &$this, 'column' ), 10, 2 );

			/* Create a hook for adding meta boxes. */
			add_action( "load-{$page_hook}", array( &$this, 'add_meta_boxes' ) );

			/* Load the JavaScript needed for the theme settings screen. */
			add_action( 'admin_enqueue_scripts', array( &$this, 'enqueue_scripts' ) );
			add_action( "admin_footer-{$page_hook}", array( &$this, 'load_scripts' ) );
		}
	}

	/**
	 * Screen Column
	 */
	public function column( $columns, $screen ) {
		$page_hook = $this->page_hook();
		if ( $screen == $page_hook )
			$columns[$page_hook] = 2;
		return $columns;
	}

	/**
	 * Enqueue script
	 */
	public function enqueue_scripts( $hook_suffix ) {
		$page_hook = $this->page_hook();
		if ( $hook_suffix == $page_hook ){
			wp_enqueue_script( 'common' );
			wp_enqueue_script( 'wp-lists' );
			wp_enqueue_script( 'postbox' );
		}
	}

	/**
	 * Print script
	 */
	public function load_scripts() { 
		$page_hook = $this->page_hook();
		?><script type="text/javascript">
			//<![CDATA[
			jQuery(document).ready( function($) {
				$('.if-js-closed').removeClass('if-js-closed').addClass('closed');
				postboxes.add_postbox_toggles( '<?php echo $page_hook; ?>' );
			});
			//]]>
		</script><?php
	}

	/**
	 * Add meta boxes
	 */
	public function add_meta_boxes() {
		do_action( 'add_meta_boxes', array( &$this, 'page_hook' ) );
	}

	/**
	 * Settings page header
	 */
	public function header() {
		$settings = $this->settings();
		$header  = get_screen_icon('options-general');
		$header .= '<h2>' . $settings['page']['page_title'] . '</h2>';
		return apply_filters( $settings['id'] . '_settings_page_header', $header );
	}

	/**
	 * Settings page html
	 */
	public function settings_page() {
		global $screen_layout_columns;
		$settings = $this->settings();
		$page_hook = $this->page_hook();

		do_action( "{$settings['id']}_before_settings_page" ); ?>

		<div class="wrap">

			<?php echo $this->header(); ?>

			<?php settings_errors(); ?>

			<?php do_action( "{$settings['id']}_open_settings_page" ); ?>

			<div class="<?php echo $settings['id']; ?>-settings-wrap">

				<form method="post" action="options.php">

					<?php settings_fields( $settings['register']['option_group'] ); ?>
					<?php wp_nonce_field( 'closedpostboxes', 'closedpostboxesnonce', false ); ?>
					<?php wp_nonce_field( 'meta-box-order', 'meta-box-order-nonce', false ); ?>

					<div id="poststuff">

						<div id="post-body" class="metabox-holder columns-2">

							<div id="postbox-container-1" class="postbox-container">

								<?php do_meta_boxes( $page_hook, 'side', null ); ?>
								<!-- #side-sortables -->

							</div><!-- #postbox-container-1 -->

							<div id="postbox-container-2" class="postbox-container">

								<?php do_meta_boxes( $page_hook, 'normal', null ); ?>
								<!-- #normal-sortables -->

								<?php do_meta_boxes( $page_hook, 'advanced', null ); ?>
								<!-- #advanced-sortables -->

							</div><!-- #postbox-container-2 -->

						</div><!-- #post-body -->

						<br class="clear">

					</div><!-- #poststuff -->

					<?php submit_button( esc_attr( $settings['submit'] ) ); ?>

				</form>

			</div><!-- .{$settings['id']}-settings-wrap -->

			<?php do_action( "{$settings['id']}_close_settings_page" ); ?>

		</div><!-- .wrap --><?php

		do_action( "{$settings['id']}_after_settings_page" );
	}
}

Hi,
Can I have proper example with all functionality (metaboxes, saving, retrieving and so on) ????